71 resultados para LONGITUDINAL ACOUSTICAL MODE
Resumo:
A series of molecular dynamics simulations of simple liquid binary mixtures of soft spheres with disparate-mass particles were carried out to investigate the origin of the marked differences between the dynamic structure factors of some liquid binary mixtures such as the Li0.7Mg0.3 and Li0.8Pb0.2 alloys. It is shown that the facility for observing peaks associated with fast-propagating modes in the partial Li-Li dynamic structure factor of Li0.8Pb0.2 should be mainly attributed to the structure of this alloy, which is characterized by an incipient ABAB ordering as found in molten salts. The longitudinal dispersion relations at intermediate wave vectors obtained from the longitudinal current spectra are very similar for the two alloys and reflect the existence of both fast-and slow-propagating modes of kinetic character associated with light and heavy particles, respectively. The influence of the hardness of the repulsive potential cores as well as the composition of the mixture on the longitudinal collective modes is also discussed.
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The nanometer¿scale oxidation of Si(100) surfaces in air is performed with an atomic force microscope working in tapping mode. Applying a positive voltage to the sample with respect to the tip, two kinds of modifications are induced on the sample: grown silicon oxide mounds less than 5 nm high and mounds higher than 10 nm (which are assumed to be gold depositions). The threshold voltage necessary to produce the modification is studied as a function of the average tip¿to¿sample distance.
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Type 1 diabetic patients depend on external insulin delivery to keep their blood glucose within near-normal ranges. In this work, two robust closed-loop controllers for blood glucose regulation are developed to prevent the life-threatening hypoglycemia, as well as to avoid extended hyperglycemia. The proposed controllers are designed by using the sliding mode control technique in a Smith predictor structure. To improve meal disturbance rejection, a simple feedforward controller is added to inject meal-time insulin bolus. Simulations scenarios were used to test the controllers, and showed the controllers ability to maintain the glucose levels within the safe limits in the presence of errors in measurements, modeling and meal estimation
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En aquest article es presenta una selecció d’un corpus extret del Pantagruel, en el qual els personatges de Rabelais ataquen o afalaguen, grotescament i hiperbòlica, en el més pur estil pantagruèlic, les altres nacions o viles. Per a aquests epítets ètnics, Rabelais reutilitza el blasó popular (blason populaire), en una fusió total de la lloança i la injúria. En el nostre treball comprovarem si la visió sociocèntrica que el blasonador aplica al blasonat, així com el propòsit lúdic, han aconseguit ser traslladats a les versions catalana (Miquel-Àngel Sánchez Férriz, 1985), espanyola (Alicia Yllera, 2003), italiana (Mario Bonfantini, 1953) i anglesa (Burton Raffel, 1991).
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In this work we explore the multivariate empirical mode decomposition combined with a Neural Network classifier as technique for face recognition tasks. Images are simultaneously decomposed by means of EMD and then the distance between the modes of the image and the modes of the representative image of each class is calculated using three different distance measures. Then, a neural network is trained using 10- fold cross validation in order to derive a classifier. Preliminary results (over 98 % of classification rate) are satisfactory and will justify a deep investigation on how to apply mEMD for face recognition.
Resumo:
Artifacts are present in most of the electroencephalography (EEG) recordings, making it difficult to interpret or analyze the data. In this paper a cleaning procedure based on a multivariate extension of empirical mode decomposition is used to improve the quality of the data. This is achieved by applying the cleaning method to raw EEG data. Then, a synchrony measure is applied on the raw and the clean data in order to compare the improvement of the classification rate. Two classifiers are used, linear discriminant analysis and neural networks. For both cases, the classification rate is improved about 20%.
Resumo:
By means of computer simulations and solution of the equations of the mode coupling theory (MCT),we investigate the role of the intramolecular barriers on several dynamic aspects of nonentangled polymers. The investigated dynamic range extends from the caging regime characteristic of glass-formers to the relaxation of the chain Rouse modes. We review our recent work on this question,provide new results, and critically discuss the limitations of the theory. Solutions of the MCT for the structural relaxation reproduce qualitative trends of simulations for weak and moderate barriers. However, a progressive discrepancy is revealed as the limit of stiff chains is approached. This dis-agreement does not seem related with dynamic heterogeneities, which indeed are not enhanced by increasing barrier strength. It is not connected either with the breakdown of the convolution approximation for three-point static correlations, which retains its validity for stiff chains. These findings suggest the need of an improvement of the MCT equations for polymer melts. Concerning the relaxation of the chain degrees of freedom, MCT provides a microscopic basis for time scales from chain reorientation down to the caging regime. It rationalizes, from first principles, the observed deviations from the Rouse model on increasing the barrier strength. These include anomalous scaling of relaxation times, long-time plateaux, and nonmonotonous wavelength dependence of the mode correlators.
Resumo:
BACKGROUND: Studies in bipolar disorder (BD) to date are limited in their ability to provide a whole-disease perspective--their scope has generally been confined to a single disease phase and/or a specific treatment. Moreover, most clinical trials have focused on the manic phase of disease, and not on depression, which is associated with the greatest disease burden. There are few longitudinal studies covering both types of patients with BD (I and II) and the whole course of the disease, regardless of patients' symptomatology. Therefore, the Wide AmbispectiVE study of the clinical management and burden of Bipolar Disorder (WAVE-bd) (NCT01062607) aims to provide reliable information on the management of patients with BD in daily clinical practice. It also seeks to determine factors influencing clinical outcomes and resource use in relation to the management of BD. METHODS: WAVE-bd is a multinational, multicentre, non-interventional, longitudinal study. Approximately 3000 patients diagnosed with BD type I or II with at least one mood event in the preceding 12 months were recruited at centres in Austria, Belgium, Brazil, France, Germany, Portugal, Romania, Turkey, Ukraine and Venezuela. Site selection methodology aimed to provide a balanced cross-section of patients cared for by different types of providers of medical aid (e.g. academic hospitals, private practices) in each country. Target recruitment percentages were derived either from scientific publications or from expert panels in each participating country. The minimum follow-up period will be 12 months, with a maximum of 27 months, taking into account the retrospective and the prospective parts of the study. Data on demographics, diagnosis, medical history, clinical management, clinical and functional outcomes (CGI-BP and FAST scales), adherence to treatment (DAI-10 scale and Medication Possession Ratio), quality of life (EQ-5D scale), healthcare resources, and caregiver burden (BAS scale) will be collected. Descriptive analysis with common statistics will be performed. DISCUSSION: This study will provide detailed descriptions of the management of BD in different countries, particularly in terms of clinical outcomes and resources used. Thus, it should provide psychiatrists with reliable and up-to-date information about those factors associated with different management patterns of BD. TRIAL REGISTRATION NO: ClinicalTrials.gov: NCT01062607.
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Gairebé han passat 20 anys d’ençà que vaig començar a reflexionar sobre la incertesa dela mà del Dr. Dídac Ramírez. Vaig presentar una tesi dirigida per ell l’any 2003, he fetarticles, he presentat comunicacions en seminaris i col·loquis. El tema de la incertesa ésmolt ampli; es relaciona amb el coneixement, l'aleatorietat, el caos, l'ètica, la psicologia,etc. En aquests 20 anys, a poc a poc, he anat lligant alguns caps i, en aquests moments,penso que pot tenir interès presentar al seminari IAFI del Departament de Matemàtiquesde la Facultat d’Econòmiques de la UB un esquema amb aquestes idees lligades enforma de vocabulari.Molts dels termes del vocabulari els proposo jo, per la qual cosa no m’he pogut limitar adonar una definició precisa i he necessitat posar explicacions i exemples per tal dejustificar el seu interès.
Resumo:
Esta comunicación, que presenta el estudio de la evolución de las creencias, representacionesy saberes (en adelante CRS) de una estudiante entre el primer año y el segundo de formaciónuniversitaria, forma parte de un estudio longitudinal más amplio que analiza los CRS de sieteestudiantes del Grado de Maestro de Educación Infantil y ocho del Grado de Maestro de EducaciónPrimaria de la Universitat de Barcelona sobre la enseñanza y el aprendizaje de la lecturay la escritura. El objetivo principal que enmarca la investigación es estudiar en profundidadlos sistemas de CRS para poder comprenderlos, compararlos e identificar los momentos clave de tensión y cambio con el fin de realizar aportaciones que ayuden a mejorar el sistema de formación inicial de los maestros.
Resumo:
Esta comunicación, que presenta el estudio de la evolución de las creencias, representacionesy saberes (en adelante CRS) de una estudiante entre el primer año y el segundo de formaciónuniversitaria, forma parte de un estudio longitudinal más amplio que analiza los CRS de sieteestudiantes del Grado de Maestro de Educación Infantil y ocho del Grado de Maestro de EducaciónPrimaria de la Universitat de Barcelona sobre la enseñanza y el aprendizaje de la lecturay la escritura. El objetivo principal que enmarca la investigación es estudiar en profundidadlos sistemas de CRS para poder comprenderlos, compararlos e identificar los momentos clave de tensión y cambio con el fin de realizar aportaciones que ayuden a mejorar el sistema de formación inicial de los maestros.
Resumo:
The development of nuclear hormone receptor antagonists that directly inhibit the association of the receptor with its essential coactivators would allow useful manipulation of nuclear hormone receptor signaling. We previously identified 3-(dibutylamino)-1-(4-hexylphenyl)-propan-1-one (DHPPA), an aromatic β-amino ketone that inhibits coactivator recruitment to thyroid hormone receptor β (TRβ), in a high-throughput screen. Initial evidence suggested that the aromatic β-enone 1-(4-hexylphenyl)-prop-2-en-1-one (HPPE), which alkylates a specific cysteine residue on the TRβ surface, is liberated from DHPPA. Nevertheless, aspects of the mechanism and specificity of action of DHPPA remained unclear. Here, we report an x-ray structure of TRβ with the inhibitor HPPE at 2.3-Å resolution. Unreacted HPPE is located at the interface that normally mediates binding between TRβ and its coactivator. Several lines of evidence, including experiments with TRβ mutants and mass spectroscopic analysis, showed that HPPE specifically alkylates cysteine residue 298 of TRβ, which is located near the activation function-2 pocket. We propose that this covalent adduct formation proceeds through a two-step mechanism: 1) β-elimination to form HPPE; and 2) a covalent bond slowly forms between HPPE and TRβ. DHPPA represents a novel class of potent TRβ antagonist, and its crystal structure suggests new ways to design antagonists that target the assembly of nuclear hormone receptor gene-regulatory complexes and block transcription.
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Peer reviewed